I cannot provide medical advice. The appearance of a lump or bump near the anus could be caused by a number of things, some minor and some requiring medical attention. It is crucial that you see a doctor or other qualified healthcare professional as soon as possible to have this examined. They can properly diagnose the cause and recommend the appropriate treatment. Delaying medical attention could potentially worsen the condition.
Do not attempt to self-diagnose or self-treat. Online information should not be substituted for a professional medical evaluation.